Comment 3 for bug 1441298

Perhaps this normal, I known this can occurs:
* when you restart rabbit, the publisher can send a message before the consumer have effectively reconnected to the broker. Before kilo, the send message was going nowhere and the publisher got a timeout error.
* if you shutdown a compute where someone have ask something through rpc as this moment.
* and also in the situation you describe, too.

Since kilo (https://review.openstack.org/#/c/109373/ ), we log "The exchange to reply to %s doesn't exist yet, retrying..." and we retry, and raise the error only if the consumer doesn't comeback after 60 seconds (ie: the queue doesn't not appear).